The lab still performs an initial Immunoassay screen with a cutoff threshold of 50 ng/ml, which is the same as the home test kits.

And if you read this post here, you'll discover that even though their cutoffs numerically differ, a 50 ng I/A screen is functionally equivalent to the 15 ng GC/MS: http://boards.cannabis.com/drug-test...ml#post2202713

If no line is present in either the "C" window or the "T" window, then either the test kit is a dud, or the test wasnt performed properly. Either way, redo the test with a different kit.

When testing yourself, be sure to use the first urination of the day. If your test is positive, then yes you can sub with the Quick Fix synthetic or a clean persons sample.